Methods for preparing polyether ester elastomer composition

ABSTRACT

Disclosed are methods for preparing polyether ester elastomer compositions having polytrimethylene ether ester soft segments and polyethylene ester hard segments and containing a nucleating agent. Shaped articles can be made from the elastomer compositions, particularly molded articles, films and fibers.

RELATED APPLICATION

This application is a continuation of, and claims priority to, currentlypending U.S. patent application Ser. No. 11/590,456, filed on Oct. 31,2006.

FIELD OF THE INVENTION

This invention relates to thermoplastic polyether ester elastomerscomprising polytrimethylene ether ester soft segment and polyethyleneterephthalate ester hard segment containing nucleating agents, methodsfor preparing the thermoplastic polyether ester elastomers, and end-usesthereof.

BACKGROUND OF THE INVENTION

Thermoplastic elastomers (TPEs) are a class of polymers which combinethe properties of two other classes of polymers, namely thermoplastics,which may be reformed upon heating, and elastomers which are rubber-likepolymers. One form of TPE is a block copolymer, usually containing someblocks whose polymer properties usually resemble those ofthermoplastics, and some blocks whose properties usually resemble thoseof elastomers. Those blocks whose properties resemble thermoplastics areoften referred to as “hard” segments, while those blocks whoseproperties resemble elastomers are often referred to as “soft” segments.It is believed that the hard segments provide properties similar tochemical crosslinks in traditional thermosetting elastomers, while thesoft segments provide rubber-like properties.

Polyether ester thermoplastic elastomers comprising polytrimethyleneether ester soft segments and tetramethylene ester hard segments areknown, for example, from U.S. Pat. No. 6,562,457. Polyether esterthermoplastic elastomers comprising polytrimethylene ether ester softsegments and trimethylene ester hard segments are known, for example,from U.S. Pat. No. 6,599,625. The polyether ester thermoplasticelastomers disclosed in these publications and useful, for example, inmaking fibers, films and other shaped articles.

Polyether ester thermoplastic elastomers comprising polytrimethyleneether ester soft segments, in particular polytrimethylene terephthalate,and polyethylene ester hard segments, in particular polyethyleneterephthalate, have also been described US20050282966A1. These flexiblematerials have a potential advantage for some uses because the meltingpoint and thermal stability of the polyethylene terephthalate hardsegments is higher than those of the hard segments based ontetramethylene or trimethylene esters. Their utility, however, has beenlimited, particularly in engineering resin applications, because oftheir relatively low rates of crystallization. In fact, the unmodifiedpolyether ester comprising polytrimethylene ether terephthalate softsegment and polyethylene terephthalate hard segment is unsuitable formost injection molding applications. Low crystallization rates cause thepolymer to be difficult to pelletize or flake, difficult to spin intofibers, and difficult to process into shaped articles by such methods asthermoforming, injection molding and blow molding, because ejection fromthe mold of an insufficiently crystallized molding would mean that thearticle could continue to crystallize when in service with appropriatevolume changes.

Additives such as crystallization nucleants and plasticizers thatimprove crystallization rates of polyesters are in a general senseknown. For example, U.S. Pat. No. 6,245,844 discloses polyestercompositions comprising poly(trimethylene dicarboxylate) and anucleating agent that is a mono sodium salt of a dicarboxylic acidselected from the group consisting of monosodium terephthalate,monosodium naphthalene dicarboxylic acid, and monosodium isophthalate.It is, however, also generally known that a specific additive that worksvery efficiently for a particular polyester may not work well forothers.

U.S. Pat. No. 3,761,450 describes molding compositions based on linearsaturated polyesters comprising small amounts of lithium and/or sodiumsalts of polycarboxylic acids to bring about a high crystallinity in theheated mold after a short time. Polyesters and salts of polycarboxylicacids are disclosed generally. Poly(ethylene terephthalate) and disodium1,10-dodecanedicarboxylate are exemplified.

U.S. Pat. No. 5,264,477 discloses an improved melt processable liquidcrystalline polyester composition capable of forming an anisotropic meltphase and having an improved heat distortion temperature under a load byusing 0.05 to 1.0 wt % of a divalent metal salt of an aromaticdicarboxylic acid, wherein the metal is zinc, calcium, cadmium, bariumor mixtures thereof.

U.S. Pat. No. 4,380,621 discloses fast crystallizing polyesters in whichat least some of the acid end groups of the polyester have the formula—COO⁻M⁺, wherein M⁺ is an alkaline metal ion. Poly(ethyleneterephthalate) and poly(butylene terephthalate) are disclosed aspolyesters. Sodium containing species exemplified include sodiumhydroxide, sodium benzoate and sodium o-chlorobenzoate.

There remains a need for nucleating agents that can improve the rate ofcrystallization of polyether ester thermoplastic elastomers comprisingpolytrimethylene ether ester soft segments and polyethylene ester hardsegments and thereby take advantage of their high melting points inproduction of fibers, films and other shaped articles.

SUMMARY OF THE INVENTION

This invention is directed to a polyether ester elastomer compositioncomprising (i) a polyether ester elastomer based on a polytrimethyleneether ester soft segment and a polyethylene ester hard segment; and (ii)a nucleating agent selected from the group consisting of an alkali metalsalt, an alkaline earth metal salt and mixtures thereof.

The amount of nucleating agent utilized is such that the polyether estercontaining nucleating agent exhibits a lower crystallization half timeand earlier onset of the crystallization time during the cooling phaseof molding, as compared to the same polyether ester without nucleatingagent (an “effective amount”).

One aspect of the present invention is a method for preparing apolyether ester elastomer, comprising providing and reacting:

(a) a polymeric ether glycol component comprising at least about 50 wt %of a polytrimethylene ether glycol;

(b) a diol component comprising at least about 50 mole % ethyleneglycol; and

(c) a dicarboxylic acid equivalent, in the presence of the nucleatingagent,

wherein the nucleating agent comprises a metal cation selected from thegroup consisting of lithium, sodium, potassium and calcium, and a anionselected from the group consisting of phosphate, sulfate and acetate;

and wherein the thus-prepared polyether ester elastomer has a Trc of atleast 183.9° C. and a T1/2 of 6.4 min or less at 215° C.

The invention also relates to shaped articles prepared from thepolyether ester, such as fibers and films.

Polyether esters containing the nucleating agents in accordance with thepresent invention exhibit short crystallization half times (t_(1/2)) andearly onsets of crystallization as measured by differential scanningcalorimeter (DSC) in the heating and cooling cycle. Crystallization halftime is the time needed for the degree of crystallinity to reach half ofits ultimate value. The higher the onset crystallization temperature(Trc), the faster the crystallization rate. The presence of thenucleating agent used in accordance with the present invention lowersthe crystallization half time of the polymer and speeds up the onset ofthe crystallization time (as well as the early appearance of thecrystallization peak temperature) during the cooling phase of thepolymer, all as measured by DSC analysis, to the extent necessary toeffectively utilize the polymer in a variety of end-use applications.

These are desirable effects because such polymers can quickly becomerigid, leading to faster demold times and shorter cycle times inprocessing them into shaped articles by such methods as thermoforming,injection molding, and blow molding. The ability to melt spin thepolyether ester into fiber is also greatly enhanced by the effects ofthe nucleating agents.

A further result achieved by the practice of this invention is theimprovement of physical properties of polyester polymers by increasingthe crystallization rate and increasing the crystallinity.

When the compositions of this invention are compared to the samepolyether ester polymers containing no nucleating agent, the polymerscontaining nucleating agent exhibit lower crystallization half times andearlier onsets of the crystallization time (early arrival of thecrystallization peak temperature) during the cooling phase. It has alsobeen found that the polyether ester comprising polytrimethylene etherester soft segment and polyethylene ester hard segment exhibitsimprovement in brittleness, heat resistance and impact resistance.

DETAILED DESCRIPTION

All publications, patent applications, patents and other referencesmentioned herein, if not otherwise indicated, are explicitlyincorporated by reference herein in their entirety for all purposes asif fully set forth.

Unless otherwise defined, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. In case of conflict, thepresent specification, including definitions, will control.

Except where expressly noted, trademarks are shown in upper case.

Unless stated otherwise, all percentages, parts, ratios, etc., are byweight.

When an amount, concentration, or other value or parameter is given aseither a range, preferred range or a list of upper preferable values andlower preferable values, this is to be understood as specificallydisclosing all ranges formed from any pair of any upper range limit orpreferred value and any lower range limit or preferred value, regardlessof whether ranges are separately disclosed. Where a range of numericalvalues is recited herein, unless otherwise stated, the range is intendedto include the endpoints thereof, and all integers and fractions withinthe range. It is not intended that the scope of the invention be limitedto the specific values recited when defining a range.

When the term “about” is used in describing a value or an end-point of arange, the disclosure should be understood to include the specific valueor end-point referred to.

As used herein, the terms “comprises,” “comprising,” “includes,”“including,” “has,” “having” or any other variation thereof, areintended to cover a non-exclusive inclusion. For example, a process,method, article, or apparatus that comprises a list of elements is notnecessarily limited to only those elements but may include otherelements not expressly listed or inherent to such process, method,article, or apparatus. Further, unless expressly stated to the contrary,“or” refers to an inclusive or and not to an exclusive or. For example,a condition A or B is satisfied by any one of the following: A is true(or present) and B is false (or not present), A is false (or notpresent) and B is true (or present), and both A and B are true (orpresent).

Use of “a” or “an” are employed to describe elements and components ofthe invention. This is done merely for convenience and to give a generalsense of the invention. This description should be read to include oneor at least one and the singular also includes the plural unless it isobvious that it is meant otherwise.

The materials, methods, and examples herein are illustrative only and,except as specifically stated, are not intended to be limiting. Althoughmethods and materials similar or equivalent to those described hereincan be used in the practice or testing of the present invention,suitable methods and materials are described herein.

In one preferred embodiment, the polyether ester composition is preparedby the steps of providing and reacting:

(a) a polytrimethylene ether glycol (“PO3G”);

(b) ethylene glycol; and

(c) a dicarboxylic acid equivalent, in the presence of the nucleatingagent.

In another preferred embodiment, the polyether ester is prepared by thesteps of:

(a) heating

(i) a polymeric ether glycol component comprising at least about 50 wt %PO3G,

(ii) terephthalic acid and/or dimethyl terephthalate,

(iii) a molar excess of a diol component comprising at least about 75mole % ethylene glycol, and

(iv) a nucleating agent selected from the group consisting of an alkalimetal salt, an alkaline earth metal salt and mixtures thereof,

in the presence of a catalyst at a temperature in the range of fromabout 150° C. to about 250° C. while removing water or methanolby-product to form a precondensation product; and

(b) polymerizing the precondensation product under vacuum at temperaturein the range of from about 220° C. to about 290° C. while removingexcess diol to form a polyether ester having polytrimethylene etherterephthalate soft segment and polyethylene terephthalate hard segment.

In yet another preferred embodiment, the polyether ester is prepared bythe steps of:

(a) heating

(i) a polymeric ether glycol component comprising at least about 50 wt %PO3G,

(ii) terephthalic acid and/or dimethyl terephthalate, and

(iii) a molar excess of a diol component comprising at least about 75mole % ethylene glycol,

in the presence of a catalyst at temperature in the range of from about150° C. to about 250° C. while removing water and/or methanol by-productto form a precondensation product;

(b) adding a nucleating agent to the precondensation product, thenucleating agent being selected from the group consisting of an alkalimetal salt, an alkaline earth metal salt and mixtures thereof; and

(c) polymerizing the precondensation product under vacuum at atemperature in the range of from about 220° C. to about 290° C. whileremoving excess diol to form a polyether ester having polytrimethyleneether terephthalate soft segment and polyethylene terephthalate hardsegment.

The polyether ester elastomer preferably comprises:

from about 10 to about 90 wt %, more preferably from about 20 to about80 wt %, and still more preferably from about 30 to about 70 wt %,polytrimethylene ether ester soft segment, and

from about 10 to about 90 wt %, more preferably from about 20 to about80 wt %, and still more preferably from about 30 to about 70 wt %,polyethylene ester hard segment,

based on the weight of the polyether ester elastomer.

The polyether ester elastomer preferably has an inherent viscosity of atleast about 0.6 dl/g, more preferably at least about 1.0 dl/g, andpreferably up to about 2.4 dl/g, more preferably up to about 1.9 dl/g.

“Polytrimethylene ether ester soft segment” and “soft segment” are usedin connection with the present invention to refer to the reactionproduct of a polymeric ether glycol and a “dicarboxylic acidequivalent”, via ester linkage, wherein at least about 50 wt %, morepreferably at least about 85 wt %, and still more preferably from about95 to 100 wt %, of the polymeric ether glycol used to form the softsegment is PO3G.

“Polyethylene ester hard segment” and “hard segment” are used inconnection with the present invention to refer to the reaction productof one or more diols and one or more dicarboxylic acid equivalents, viaester linkage, wherein greater than about 50 mole %, more preferably atleast about 75 mole %, even more preferably at least about 85 mole %,and still more preferably from about 95 to 100 mole %, of the diol usedto form the hard segment is ethylene glycol.

By “dicarboxylic acid equivalent” is meant dicarboxylic acids and theirequivalents, which are compounds that perform substantially likedicarboxylic acids in reaction with polymeric glycols and diols, aswould be generally recognized by a person of ordinary skill in therelevant art. In addition to dicarboxylic acids, dicarboxylic acidequivalents for the purpose of the present invention include, forexample, mono- and diesters of dicarboxylic acids, and diester-formingderivatives such as acid halides (e.g., acid chlorides) and anhydrides.

Polymeric Ether Glycol for Soft Segment

PO3G for the purposes of the present invention is an oligomic and/orpolymeric ether glycol in which at least 50% of the repeating units aretrimethylene ether units. More preferably from about 75% to 100%, stillmore preferably from about 90% to 100%, and even more preferably fromabout 99% to 100%, of the repeating units are trimethylene ether units.

PO3G is preferably prepared by polycondensation of monomers comprising1,3-propanediol, thus resulting in polymers or copolymers containing—(CH₂CH₂CH₂O)— linkage (e.g, trimethylene ether repeating units).

In addition to the trimethylene ether units, lesser amounts of otherunits, such as other polyalkylene ether repeating units, may be present.In the context of this disclosure, the term “polytrimethylene etherglycol” encompasses PO3G made from essentially pure 1,3-propanediol, aswell as those oligomers and polymers (including those described below)containing up to 50% by weight of comonomers.

The 1,3-propanediol employed for preparing the PO3G may be obtained byany of the various well known chemical routes or by biochemicaltransformation routes. Preferred routes are described in, for example,U.S. Pat. No. 5,015,789, U.S. Pat. No. 5,276,201, U.S. Pat. No.5,284,979, U.S. Pat. No. 5,334,778, U.S. Pat. No. 5,364,984, U.S. Pat.No. 5,364,987, U.S. Pat. No. 5,633,362, U.S. Pat. No. 5,686,276, U.S.Pat. No. 5,821,092, U.S. Pat. No. 5,962,745, U.S. Pat. No. 6,140,543,U.S. Pat. No. 6,232,511, U.S. Pat. No. 6,235,948, U.S. Pat. No.6,277,289, U.S. Pat. No. 6,297,408, U.S. Pat. No. 6,331,264, U.S. Pat.No. 6,342,646, U.S. Pat. No. 7,038,092, US20040225161A1,US20040260125A1, US20040225162A1 and US20050069997A1.

Preferably, the 1,3-propanediol is obtained biochemically from arenewable source (“biologically-derived” 1,3-propanediol).

A particularly preferred source of 1,3-propanediol is via a fermentationprocess using a renewable biological source. As an illustrative exampleof a starting material from a renewable source, biochemical routes to1,3-propanediol (PDO) have been described that utilize feedstocksproduced from biological and renewable resources such as corn feedstock. For example, bacterial strains able to convert glycerol into1,3-propanediol are found in the species Klebsiella, Citrobacter,Clostridium, and Lactobacillus. The technique is disclosed in severalpublications, including previously incorporated U.S. Pat. No. 5,633,362,U.S. Pat. No. 5,686,276 and U.S. Pat. No. 5,821,092. U.S. Pat. No.5,821,092 discloses, inter alia, a process for the biological productionof 1,3-propanediol from glycerol using recombinant organisms. Theprocess incorporates E. coli bacteria, transformed with a heterologouspdu diol dehydratase gene, having specificity for 1,2-propanediol. Thetransformed E. coli is grown in the presence of glycerol as a carbonsource and 1,3-propanediol is isolated from the growth media. Since bothbacteria and yeasts can convert glucose (e.g., corn sugar) or othercarbohydrates to glycerol, the processes disclosed in these publicationsprovide a rapid, inexpensive and environmentally responsible source of1,3-propanediol monomer.

The biologically-derived 1,3-propanediol, such as produced by theprocesses described and referenced above, contains carbon from theatmospheric carbon dioxide incorporated by plants, which compose thefeedstock for the production of the 1,3-propanediol. In this way, thebiologically-derived 1,3-propanediol preferred for use in the context ofthe present invention contains only renewable carbon, and not fossilfuel-based or petroleum-based carbon. The PO3G and elastomers basedthereon utilizing the biologically-derived 1,3-propanediol, therefore,have less impact on the environment as the 1,3-propanediol used in thecompositions does not deplete diminishing fossil fuels and, upondegradation, releases carbon back to the atmosphere for use by plantsonce again. Thus, the compositions of the present invention can becharacterized as more natural and having less environmental impact thansimilar compositions comprising petroleum based glycols.

The biologically-derived 1,3-propanediol, and PO3G and elastomers basedthereon, may be distinguished from similar compounds produced from apetrochemical source or from fossil fuel carbon by dual carbon-isotopicfinger printing. This method usefully distinguishes chemically-identicalmaterials, and apportions carbon in the copolymer by source (andpossibly year) of growth of the biospheric (plant) component. Theisotopes, ¹⁴C and ¹³C, bring complementary information to this problem.The radiocarbon dating isotope (¹⁴C), with its nuclear half life of 5730years, clearly allows one to apportion specimen carbon between fossil(“dead”) and biospheric (“alive”) feedstocks (Currie, L. A. “SourceApportionment of Atmospheric Particles,” Characterization ofEnvironmental Particles, J. Buffle and H. P. van Leeuwen, Eds., 1 ofVol. I of the IUPAC Environmental Analytical Chemistry Series (LewisPublishers, Inc) (1992) 3-74). The basic assumption in radiocarbondating is that the constancy of ¹⁴C concentration in the atmosphereleads to the constancy of ¹⁴C in living organisms. When dealing with anisolated sample, the age of a sample can be deduced approximately by therelationship:

t=(−5730/0.693)ln(A/A ₀)

wherein t=age, 5730 years is the half-life of radiocarbon, and A and A₀are the specific ¹⁴C activity of the sample and of the modern standard,respectively (Hsieh, Y., Soil Sci. Soc. Am J., 56, 460, (1992)).However, because of atmospheric nuclear testing since 1950 and theburning of fossil fuel since 1850, ¹⁴C has acquired a second,geochemical time characteristic. Its concentration in atmospheric CO₂,and hence in the living biosphere, approximately doubled at the peak ofnuclear testing, in the mid-1960s. It has since been gradually returningto the steady-state cosmogenic (atmospheric) baseline isotope rate(¹⁴C/¹²C) of ca. 1.2×10⁻¹², with an approximate relaxation “half-life”of 7-10 years. (This latter half-life must not be taken literally;rather, one must use the detailed atmospheric nuclear input/decayfunction to trace the variation of atmospheric and biospheric ¹⁴C sincethe onset of the nuclear age.) It is this latter biospheric ¹⁴C timecharacteristic that holds out the promise of annual dating of recentbiospheric carbon. ¹⁴C can be measured by accelerator mass spectrometry(AMS), with results given in units of “fraction of modern carbon”(f_(M)). f_(M) is defined by National Institute of Standards andTechnology (NIST) Standard Reference Materials (SRMs) 4990B and 4990C,known as oxalic acids standards HOxI and HOxII, respectively. Thefundamental definition relates to 0.95 times the ¹⁴C/¹²C isotope ratioHOxI (referenced to AD 1950). This is roughly equivalent todecay-corrected pre-Industrial Revolution wood. For the current livingbiosphere (plant material), f_(M)≈1.1.

The stable carbon isotope ratio (¹³C/¹²C) provides a complementary routeto source discrimination and apportionment. The ¹³C/¹²C ratio in a givenbiosourced material is a consequence of the ¹³C/¹²C ratio in atmosphericcarbon dioxide at the time the carbon dioxide is fixed and also reflectsthe precise metabolic pathway. Regional variations also occur.Petroleum, C₃ plants (the broadleaf), C₄ plants (the grasses), andmarine carbonates all show significant differences in ¹³C/¹²C and thecorresponding δ¹³C values. Furthermore, lipid matter of C₃ and C₄ plantsanalyze differently than materials derived from the carbohydratecomponents of the same plants as a consequence of the metabolic pathway.Within the precision of measurement, ¹³C shows large variations due toisotopic fractionation effects, the most significant of which for theinstant invention is the photosynthetic mechanism. The major cause ofdifferences in the carbon isotope ratio in plants is closely associatedwith differences in the pathway of photosynthetic carbon metabolism inthe plants, particularly the reaction occurring during the primarycarboxylation, i.e., the initial fixation of atmospheric CO₂. Two largeclasses of vegetation are those that incorporate the “C₃” (orCalvin-Benson) photosynthetic cycle and those that incorporate the “C₄”(or Hatch-Slack) photosynthetic cycle. C₃ plants, such as hardwoods andconifers, are dominant in the temperate climate zones. In C₃ plants, theprimary CO₂ fixation or carboxylation reaction involves the enzymeribulose-1,5-diphosphate carboxylase and the first stable product is a3-carbon compound. C₄ plants, on the other hand, include such plants astropical grasses, corn and sugar cane. In C₄ plants, an additionalcarboxylation reaction involving another enzyme, phosphenol-pyruvatecarboxylase, is the primary carboxylation reaction. The first stablecarbon compound is a 4-carbon acid, which is subsequentlydecarboxylated. The CO₂ thus released is refixed by the C₃ cycle.

Both C₄ and C₃ plants exhibit a range of ¹³C/¹²C isotopic ratios, buttypical values are ca. −10 to −14 per mil (C₄) and −21 to −26 per mil(C₃) (Weber et al., J. Agric. Food Chem., 45, 2942 (1997)). Coal andpetroleum fall generally in this latter range. The ¹³C measurement scalewas originally defined by a zero set by pee dee belemnite (PDB)limestone, where values are given in parts per thousand deviations fromthis material. The “δ¹³C” values are in parts per thousand (per mil),abbreviated ‰, and are calculated as follows:

${\delta^{13}C} \equiv {\frac{{( {{\,^{13}C}/{\,^{12}C}} )\mspace{14mu} {sample}} - {( {{\,^{13}C}/{\,^{12}C}} )\mspace{14mu} {standard}}}{( {{\,^{13}C}/{\,^{12}C}} )\mspace{14mu} {standard}} \times 1000{{^\circ}/{{^\circ}{^\circ}}}}$

Since the PDB reference material (RM) has been exhausted, a series ofalternative RMs have been developed in cooperation with the IAEA, USGS,NIST, and other selected international isotope laboratories. Notationsfor the per mil deviations from PDB is δ¹³C. Measurements are made onCO₂ by high precision stable ratio mass spectrometry (IRMS) on molecularions of masses 44, 45 and 46.

Biologically-derived 1,3-propanediol, and compositions comprisingbiologically-derived 1,3-propanediol, therefore, may be completelydistinguished from their petrochemical derived counterparts on the basisof ¹⁴C (f_(m)) and dual carbon-isotopic fingerprinting, indicating newcompositions of matter. The ability to distinguish these products isbeneficial in tracking these materials in commerce. For example,products comprising both “new” and “old” carbon isotope profiles may bedistinguished from products made only of “old” materials. Hence, theinstant materials may be followed in commerce on the basis of theirunique profile and for the purposes of defining competition, fordetermining shelf life, and especially for assessing environmentalimpact.

Preferably the 1,3-propanediol used as the reactant or as a component ofthe reactant will have a purity of greater than about 99%, and morepreferably greater than about 99.9%, by weight as determined by gaschromatographic analysis. Particularly preferred are the purified1,3-propanediols as disclosed in previously incorporated U.S. Pat. No.7,038,092, US20040260125A1, US20040225161A1 and US20050069997A1, as wellas PO3G made therefrom as disclosed in US20050020805A1.

The purified 1,3-propanediol preferably has the followingcharacteristics:

(1) an ultraviolet absorption at 220 nm of less than about 0.200, and at250 nm of less than about 0.075, and at 275 nm of less than about 0.075;and/or

(2) a composition having L*a*b* “b*” color value of less than about 0.15

(ASTM D6290), and an absorbance at 270 nm of less than about 0.075;and/or

(3) a peroxide composition of less than about 10 ppm; and/or

(4) a concentration of total organic impurities (organic compounds otherthan 1,3-propanediol) of less than about 400 ppm, more preferably lessthan about 300 ppm, and still more preferably less than about 150 ppm,as measured by gas chromatography.

The starting material for making PO3G will depend on the desired PO3G,availability of starting materials, catalysts, equipment, etc., andcomprises “1,3-propanediol reactant.” By “1,3-propanediol reactant” ismeant 1,3-propanediol, and oligomers and prepolymers of 1,3-propanediolpreferably having a degree of polymerization of 2 to 9, and mixturesthereof. In some instances, it may be desirable to use up to 10% or moreof low molecular weight oligomers where they are available. Thus,preferably the starting material comprises 1,3-propanediol and the dimerand trimer thereof. A particularly preferred starting material iscomprised of about 90% by weight or more 1,3-propanediol, and morepreferably about 99% by weight or more 1,3-propanediol, based on theweight of the 1,3-propanediol reactant.

PO3G can be made via a number of processes known in the art, such asdisclosed in U.S. Pat. No. 6,977,291 and U.S. Pat. No. 6,720,459. Apreferred process is as set forth in previously incorporatedUS20050020805A1.

As indicated above, PO3G may contain lesser amounts of otherpolyalkylene ether repeating units in addition to the trimethylene etherunits. The monomers for use in preparing polytrimethylene ether glycolcan, therefore, contain up to 50% by weight (preferably about 20 wt % orless, more preferably about 10 wt % or less, and still more preferablyabout 2 wt % or less), of comonomer polyols in addition to the1,3-propanediol reactant. Suitable comonomer polyols include aliphaticdiols, for example, ethylene glycol, 1,6-hexanediol, 1,7-heptanediol,1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol,3,3,4,4,5,5-hexafluoro-1,5-pentanediol,2,2,3,3,4,4,5,5-octafluoro-1,6-hexanediol, and3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10-hexadecafluoro-1,12-dodecanediol;cycloaliphatic diols, for example, 1,4-cyclohexanediol,1,4-cyclohexanedimethanol and isosorbide; and polyhydroxy compounds, forexample, glycerol, trimethylolpropane and pentaerythritol. A preferredgroup of comonomer diols is selected from the group consisting ofethylene glycol, 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol,2,2-diethyl-1,3-propanediol, 2-ethyl-2-(hydroxymethyl)-1,3-propanediol,C₆-C₁₀ diols (such as 1,6-hexanediol, 1,8-octanediol and1,10-decanediol) and isosorbide, and mixtures thereof. Particularlypreferred diols other than 1,3-propanediol include ethylene glycol,2-methyl-1,3-propanediol and C₆-C₁₀ diols.

One preferred PO3G containing comonomers is poly(trimethylene-ethyleneether) glycol such as described in US20040030095A1. Preferredpoly(trimethylene-ethylene ether) glycols are prepared by acid catalyzedpolycondensation of from greater than 50 to about 99 mole % (preferablyfrom about 60 to about 98 mole %, and more preferably from about 70 toabout 98 mole %) 1,3-propanediol, and up to 50 to about 1 mole %(preferably from about 40 to about 2 mole %, and more preferably fromabout 30 to about 2 mole %) ethylene glycol.

Preferably, the PO3G after purification has essentially no acid catalystend groups, but may contain very low levels of unsaturated end groups,predominately allyl end groups, in the range of from about 0.003 toabout 0.03 meq/g. Such a PO3G can be considered to comprise (consistessentially of) the compounds having the following formulae (II) and(III):

HO—((CH₂)₃O)_(m)—H  (II)

HO—((CH₂)₃—O)_(m)CH₂CH═CH₂  (III)

wherein m is in a range such that the Mn (number average molecularweight) is within the range of from about 200 to about 5000, withcompounds of formula (III) being present in an amount such that theallyl end groups (preferably all unsaturation ends or end groups) arepresent in the range of from about 0.003 to about 0.03 meq/g. The smallnumber of allyl end groups in the PO3G are useful to control elastomermolecular weight, while not unduly restricting it, so that compositionsideally suited, for example, for fiber end-uses can be prepared.

The preferred PO3G for use in the invention has an Mn of at least about250, more preferably at least about 1000, and still more preferably atleast about 2000. The Mn is preferably less than about 5000, morepreferably less than about 4000, and still more preferably less thanabout 3500. Blends of PO3Gs can also be used. For example, the PO3G cancomprise a blend of a higher and a lower molecular weight PO3G,preferably wherein the higher molecular weight PO3G has a number averagemolecular weight of from about 1000 to about 5000, and the lowermolecular weight PO3G has a number average molecular weight of fromabout 200 to about 950. The Mn of the blended PO3G will preferably stillbe in the ranges mentioned above.

PO3G preferred for use herein is typically a polydisperse polymer havinga polydispersity (i.e. Mw/Mn) of preferably from about 1.0 to about 2.2,more preferably from about 1.2 to about 2.2, and still more preferablyfrom about 1.5 to about 2.1. The polydispersity can be adjusted by usingblends of PO3G.

PO3G for use in the present invention preferably has a color value ofless than about 100 APHA, and more preferably less than about 50 APHA.

When a PO3G based substantially on 1,3-propanediol is used to form thesoft segment, the soft segment can be represented as comprising unitsrepresented by the following structure:

wherein R represents a divalent radical remaining after removal ofcarboxyl functionalities from a dicarboxylic acid equivalent, and x is awhole number representing the number of trimethylene ether units in thePO3G.

The polymeric ether glycol used to prepare the polytrimethylene etherester soft segment of the polyether ester may also include up to 50 wt %of a polymeric ether glycol other than PO3G. Preferred such otherpolymeric ether glycols include, for example, polyethylene ether glycol,polypropylene ether glycol, polytetramethylene ether glycol,polyhexamethylene ether glycol, copolymers of tetrahydrofuran and3-alkyl tetrahydrofuran, and mixtures thereof.

Diol for Hard Segment

When ethylene glycol is used to form the hard segment, the hard segmentcan be represented as comprising units having the following structure:

wherein R′ represents a divalent radical remaining after removal ofcarboxyl functionalities from a dicarboxylic acid equivalent. In mostcases, the dicarboxylic acid equivalents used to prepare the softsegment and the hard segment of the polyether ester of this inventionwill be the same.

The hard segment can also be prepared with less than 50 mole %,preferably up to about 25 mole %, more preferably up to about 15 mole %,and still more preferably up to about 5 mole %, of diols other thanethylene glycol, preferably having a molecular weight lower than about400. The other diols are preferably aliphatic diols and can be acyclicor cyclic. Preferred are diols with 3-15 carbon atoms such astrimethylene, tetramethylene, isobutylene, butylene, pentamethylene,2,2-dimethyltrimethylene, 2-methyltrimethylene, hexamethylene anddecamethylene glycols; dihydroxy cyclohexane; cyclohexane dimethanol;and hydroquinone bis(2-hydroxyethyl)ether. More preferred are aliphaticdiols containing 3-8 carbon atoms, especially 1,3-propanediol(trimethylene glycol) and/or 1,4-butanediol (tetramethylene glycol). Twoor more other diols can be used.

Dicarboxylic Acid Equivalent

The dicarboxylic acid equivalent can be aromatic, aliphatic orcycloaliphatic. In this regard, “aromatic dicarboxylic acid equivalents”are dicarboxylic acid equivalents in which each carboxyl group isattached to a carbon atom in a benzene ring system such as thosementioned below. “Aliphatic dicarboxylic acid equivalents” aredicarboxylic acid equivalents in which each carboxyl group is attachedto a fully saturated carbon atom or to a carbon atom which is part of anolefinic double bond. If the carbon atom is in a ring, the equivalent is“cycloaliphatic.” The dicarboxylic acid equivalent can contain anysubstituent groups or combinations thereof, so long as the substituentgroups do not interfere with the polymerization reaction or adverselyaffect the properties of the polyether ester product.

Preferred are the dicarboxylic acid equivalents selected from the groupconsisting of dicarboxylic acids and diesters of dicarboxylic acids.More preferred are dimethyl esters of dicarboxylic acids.

Preferred are the aromatic dicarboxylic acids or diesters by themselves,or with small amounts of aliphatic or cycloaliphatic dicarboxylic acidsor diesters. Especially preferred are the dimethyl esters of aromaticdicarboxylic acids.

Representative aromatic dicarboxylic acids useful in the presentinvention include terephthalic acid, isophthalic acid, bibenzoic acid,naphthalic acid, substituted dicarboxylic compounds with benzene nucleisuch as bis(p-carboxyphenyl)methane, 1,5-naphthalene dicarboxylic acid,2,6-naphthalene dicarboxylic acid, 2,7-naphthalene dicarboxylic acid,4,4′-sulfonyl dibenzoic acid, and C1-C10 alkyl and other ringsubstitution derivatives such as halo, alkoxy or aryl derivatives.Hydroxy acids such as p-(hydroxyethoxy)benzoic acid can also be usedproviding an aromatic dicarboxylic acid is also present. Representativealiphatic and cycloaliphatic dicarboxylic acids useful in this inventionare sebacic acid, 1,3- or 1,4-cyclohexane dicarboxylic acid, adipicacid, dodecanedioic acid, glutaric acid, succinic acid, oxalic acid,azelaic acid, diethylmalonic acid, fumaric acid, citraconic acid,allylmalonate acid, 4-cyclohexene-1,2-dicarboxylate acid, pimelic acid,suberic acid, 2,5-diethyladipic acid, 2-ethylsuberic acid,2,2,3,3-tetramethyl succinic acid, cyclopentanenedicarboxylic acid,decahydro-1,5- (or 2,6-)naphthalene dicarboxylic acid, 4,4′-bicyclohexyldicarboxylic acid, 4,4′methylenebis(cyclohexylcarboxylic acid),3,4-furan dicarboxylate, and 1,1-cyclobutane dicarboxylate. Thedicarboxylic acid equivalents in the form of diesters, acid halides andanhydrides of the aforementioned aliphatic dicarboxylic acids are alsouseful to provide the polyether ester of the present invention.Representative aromatic diesters include dimethyl terephthalate,bibenzoate, isophthlate, phthalate and naphthalate.

Of the above, preferred are terephthalic, bibenzoic, isophthalic andnaphthalic acid; dimethyl terephthalate, bibenzoate, isophthlate,naphthalate and phthalate; and mixtures thereof. Particularly preferreddicarboxylic acid equivalents are the equivalents of phenylenedicarboxylic acids especially those selected from the group consistingof terephthalic and isophthalic acid and their diesters, especially thedimethyl esters, dimethyl terephthalate and dimethyl isophthalate. Inaddition, two or more dicarboxylic acids equivalents can be used. Forinstance, terephthalic acid and/or dimethyl terephthalate can be usedwith small amounts of the other dicarboxylic acid equivalents.

In a preferred embodiment, at least about 70 mole % (more preferably atleast about 80 mole %, still more preferably at least about 90 mole %,and still more preferably from about 95 to 100 mole %) of thedicarboxylic acid equivalent is terephthalic acid and/or dimethylterephthalate.

Nucleating Agent

The compositions of the invention include a nucleating agent. Preferrednucleating agents for use in the invention are alkali metal (Group IA)or alkaline earth metal (Group IIA) salts of, for example, sulfinates,phosphinates, phosphates, sulfates, sulfonates, phosphates, hydroxides,aliphatic carboxylates and aromatic carboxylates. That is, the saltscomprise an alkali metal (lithium, sodium, potassium, rubidium orcesium) or alkaline earth metal (magnesium, calcium, strontium, orbarium) cation and an anion preferably selected from the groupconsisting of carboxylate, sulfinate, phosphinate, sulfate, sulfonate,phosphate, hydroxide, aliphatic carboxylate and aromatic carboxylate.Preferred metal cations are lithium, sodium, potassium and calcium.Preferred anions are phosphate, sulfate, aliphatic carboxylates such asacetate and propionate, and aromatic carboxylates such as benzoate acid,terephthalate, isophthalate and phthalate. Particularly preferrednucleating agents are trisodium phosphate and sodium acetate.

Preferably the nucleating agent is present at a level of from about0.005 to about 2 wt %, and more preferably from about 0.01 to about 1 wt%, based on the weight of the polyethylene ester hard segment.

Process of Making

The polyether ester is preferably prepared by providing and reacting (a)a PO3G, (b) ethylene glycol and (c) a dicarboxylic acid equivalent. Theother glycols, diols, etc., as described above are can also be providedand reacted.

The polyether ester of this invention is conveniently made starting witha conventional ester exchange reaction, esterification ortransesterification depending on the starting dicarboxylic acidequivalent. For example, dimethyl terephthalate is heated withpolytrimethylene ether glycol and an excess of ethylene glycol in thepresence of a catalyst at 150-250° C., while distilling off the methanolformed by the ester exchange. This reaction is typically performed at apressure of about 1 atmosphere. The reaction product, referred to hereinas “precondensation product”, is a mixture of the ester exchangereaction products of the dimethyl terephthalate and the polytrimethyleneether glycol and ethylene glycol, primarily bis(hydroxyethyl)terephthalate with varying amounts of (hydroxypolytrimethylene ether)terephthalates, along with a small amount of the correspondingoligomers. This precondensation product mixture then undergoespolymerization or polycondensation to a copolymer of an elastomericpolyether ester with a polytrimethylene ether glycol soft segment and apolyethylene terephthalate hard segment (condensation product ofethylene glycol and dimethyl terephthalate). The polymerization(polycondensation) involves additional ester exchange and distillationto remove the diol to increase molecular weight. The polycondensation istypically performed under vacuum. Pressure is typically in the range offrom about 0.01 to about 18 mm Hg (1.3 to 2400 Pa), preferably in therange of from about 0.05 to about 4 mm Hg (6.7 to 553 Pa), and morepreferably from about 0.05 to about 2 mm Hg. The polycondensation istypically carried out at a temperature in the range of from about 220°C. to about 290° C.

The precondensation (ester exchange) and polymerization steps mayinvolve alternative processes than those described above. For example,polytrimethylene ether glycol can be reacted with polydimethylene ester(e.g., polyethylene terephthalate) in the presence of catalyst (such asthose described for the ester exchange, preferably the titaniumcatalysts such as tetrabutyl titanate) until randomization occurs. Bothprocesses result in block copolymers.

To avoid excessive residence time at high temperatures and possibleaccompanying thermal degradation, a catalyst can be (and preferably is)employed in the ester exchange. Catalysts useful in the ester exchangeprocess include organic and inorganic compounds of titanium, lanthanum,tin, antimony, zirconium, manganese, zinc, phosphorus and mixturesthereof. Manganese acetate is a preferred transesterification catalystand antimony trioxide is a preferred polycondensation catalyst. Titaniumcatalysts, such as tetraisopropyl titanate and tetrabutyl titanate, arealso preferred and are added in an amount of at least about 25 ppm(preferably at least about 50 ppm and more preferably at least about 100ppm) and up to about 1000 ppm (preferably up to about 500 ppm and morepreferably up to about 400 ppm) titanium by weight, based on the weightof the finished polymer. Additional catalyst may be added after esterexchange or direct esterification reaction and prior to polymerization.

Ester exchange polymerizations are generally conducted in the meltwithout added solvent, but inert solvents can be added to facilitateremoval of volatile components, such as water and diols at lowtemperatures. This technique is useful during reaction of thepolytrimethylene ether glycol or the diol with the dicarboxylic acidequivalent, especially when it involves direct esterification, i.e., thedicarboxylic acid equivalent is a diacid. Other special polymerizationtechniques can be useful for preparation of specific polymers.Polymerization (polycondensation) can also be accomplished in the solidphase by heating divided solid product from the reaction ofpolytrimethylene ether glycol, a dicarboxylic acid equivalent, andethylene glycol in a vacuum or in a stream of inert gas to removeliberated diol. This type of polycondensation is referred to herein as“solid phase polymerization” (or abbreviated “SPP”).

Batch or continuous methods can be used for the processes describedabove or for any stage of polyether ester preparation. Continuouspolymerization, by ester exchange, is preferred.

In preparing the polyether ester elastomers of this invention, it issometimes desirable to incorporate known branching agents to increasemelt strength. In such instances, a branching agent is typically used ina concentration of from about 0.00015 to about 0.005 equivalents per 100grams of polymer. The branching agent can be a polyol having 3-6hydroxyl groups, a polycarboxylic acid having 3 or 4 carboxyl groups, ora hydroxy acid having a total of 3-6 hydroxyl and carboxyl groups.Representative polyol branching agents include glycerol, sorbitol,pentaerytritol, 1,1,4,4-tetrakis(hydroxymethyl)cyclohexane, trimethylolpropane, and 1,2,6-hexane triol. Suitable polycarboxylic acid branchingagents include hemimellitic, trimellitic, trimesic pyromellitic,1,1,2,2-ethanetetracarboxylic, 1,1,2-ethanetricarboxylic,1,3,5-pentanetricarboxylic, 1,2,3,4-cyclopentanetetracarboxylic and likeacids. Although the acids can be used as is, it is preferred to use themin the form of their lower alkyl esters.

Properties of the polyether ester will be influenced by varying thecomposition (dicarboxylic acid equivalent, ethylene glycol,polytrimethylene ether glycol, other diol, other glycol, etc.), theweight % of hard segment, and the mole ratio of hard segment to softsegment. Depending on amount of polytrimethylene ether glycolincorporated, a soft rubbery elastomer to a hard resin can be made. Thepreferred amount of polytrimethylene ether glycol for soft grade polymeris from about 60 to about 90%, for medium grade polymer is from about 30to about 59% and for hard grade polymer is from about 1 to about 29%, byweight based on the weight of the polymer. The preferred molecularweight (Mn) of polytrimethylene ether glycol for soft polymer is fromabout 1500 to about 5000, for a medium grade polymer is from about 800to about 2000, and a hard grade polymer is from about 250 to about 1200.

The nucleating agent can be introduced to the polyether ester in severalways. It can be added at any time during the synthesis of the polymer.That is, it can be added during the (trans)esterification and/or thepolycondensation steps. It is also possible to mix the nucleating agentwith the finished polyether ester while it is being processed in anextruder or other melt mixer. Preferably, the nucleating agent is addedduring the (trans)esterification stage. It may be added as a purecompound or as a masterbatch in the same or different polyether ester towhich it is being added.

The compositions of the present invention may include a plasticizer toimprove their processability. Preferred plasticizers include, forexample, diesters of polyethylene glycol such as diethylene glycoldi(2-ethylhexonate), triethylene glycol di(2-ethylhexonate),tetraethylene glycol diheptanoate, triethylene glycoldi(2-ethylbutyrate), di-2-ethylhexyl phthalate, and di-2-ethylhexyladipate, The preferred amount of plasticizer in the composition is fromabout 0.1 to about 15%, and more preferably from about 1 to about 10%,by weight based on the total weight of the polymer.

Besides nucleating agents and plasticizers, the compositions of thepresent invention may also include other well-known additives such asantioxidants, branching agents, heat and UV stabilizers, fillers, dyes,pigments and epoxides.

End Uses of the Polyether Esters

The nucleated polyether esters of this invention are useful, forexample, in making fibers, films and other shaped articles.

The fibers include monocomponent and multicomponent fiber such asbicomponent fiber (containing the polyether ester as at least onecomponent), and can be continuous filaments or staple fiber. The fibersare used to prepare woven, knit and nonwoven fabrics. The nonwovenfabrics can be prepared using conventional techniques such as use formeltblown, spunbonded and card and bond fabrics, including heat bonding(hot air and point bonding), air entanglement, etc.

Yarns (also known as “bundles”) preferably comprise at least about 2,and more preferably at least about 25 filaments. The yarns typicallyhave a total denier of from about 1 to about 500, preferably at leastabout 20, more preferably at least about 50, and even more preferablyfrom about 50 to about 100. Filaments are preferably at least about 0.5denier per filament (dpf), more preferably at least about 1 dpf, and upto about 20 or more dpf, more preferably up to about 10 dpf. Typicalfilaments are about 3 to 10 dpf, and fine filaments are about 0.5 toabout 2.5 dpf.

Spinning speeds can be at least about 200 meters/minute (m/min), morepreferably at least about 1000 m/min, and ever more preferably at leastabout 500 m/min, and can be up to about 4000 m/min or higher.

The fibers can be drawn from about 1.5× to about 6×, preferably at leastabout 1.5×, and preferably up to about 4×. Single step draw is thepreferred drawing technique. In most cases it is preferred not to drawthe fibers.

The fibers can be heat set, and preferably the temperature is at leastabout 140° C. and preferably up to about 160° C.

Finishes can be applied for spinning or subsequent processing, andinclude silicon oil, mineral oil, and other spin finishes used forpolyesters and polyether ester elastomers, etc.

The fibers are stretchy, have good chlorine resistance, can be dyedunder normal polyester dyeing conditions, and have excellent physicalproperties, including superior strength and stretch recovery properties,particularly improved unload power and stress decay.

Conventional additives can be incorporated into the polyether ester orfiber by known techniques. The additives include delusterants (e.g.,TiO₂, zinc sulfide and/or zinc oxide), colorants (e.g., dyes),stabilizers (e.g., antioxidants, ultraviolet light stabilizers, heatstabilizers, etc.), fillers, flame retardants, pigments, antimicrobialagents, antistatic agents, optical brighteners, extenders, processingaids, viscosity boosters, and other functional additives.

Particularly useful shaped articles are flexible films and sheets,particularly those having a thickness of from about 1 μm to about 500μm. The shaped article may, for example, comprise multilayers wherein atleast one layer has a thickness of about 5 um or less.

The present invention provides flexible films comprisingpolytrimethylene ether ester elastomers having desirable mechanicalproperties such as tenacity, elasticity, toughness and flexibility,optionally without the use of plasticizers. In addition, the films alsopossess very good breathability (high water vapor permeation rates).Such films can be useful in making bags and packaging, e.g., for food,storage and transportation. The films can be prepared from the polymersusing methods known to those skilled in the art. The flexible films canbe cast films or oriented films Oriented films can be uniaxiallyoriented or biaxially oriented. Orientation can be effected by anyprocess known in the art, such as, for example a tubular or flat filmprocess. Orientation of films is disclosed, for example, in WO01/48062.

EXAMPLES

The following examples are presented for the purpose of illustrating theinvention and are not intended to be limiting. All parts, percentages,etc., are by weight unless otherwise indicated.

The 1,3-propanediol utilized in the examples was prepared by biologicalmethods described in US2005/0069997A1, and had a purity of >99.8%

PO3G was prepared from 1,3-propanediol as described in US20050020805A1.

Number-average molecular weights (Mn) were determined by end-groupanalysis using NMR spectroscopic methods.

Melting point (Tm), (re)crystallization temperature (Trc), glasstransition temperature (Tg), and ΔH (the heat caused by the polymercrystallization) were determined in accordance with ASTM D-3418 (1988)using a DuPont DSC Instrument Model 2100 (E.I. du Pont de Nemours andCo., Wilmington, Del.). About 3 mg of sample was sealed in a DSCaluminum pan and the sample was heated to 270° C. under a nitrogenatmosphere and then cooled. The heating and cooling rates were 10° C.per minute.

Crystallization behavior of polyether ester elastomers was investigatedby differential scanning calorimetry (DSC). The inherent viscosity (IV)of the polymer sample was analyzed on a PolyVISC® automated viscometer(Cannon Instrument Co.) at a temperature of 30° C. in m-cresol with a0.5% concentration.

Comparative Example 1

This comparative example describes the synthesis of a polyether esterhaving 45 wt % polyethylene terephthalate and 5 wt % polybutyleneterephthalate hard segments, and 50 wt % polytrimethylene etherterephthalate soft segment. No nucleating agent was utilized.

A 25 gallon autoclave was charged with 33.2 lbs of dimethylterephthalate, 30 lbs of PO3G (Mn of 2250), 14 lbs of ethylene glycol, 2lbs of 1,4-butanediol, 80 g of ETHANOX® 330 antioxidant (Albemarle), and12 g of TYZOR® TPT catalyst (E.I. DuPont de Nemours and Company). Thereactant charge was designed to achieve a weight ratio of polyethyleneterephthalate:polybutylene terephthalate:polytrimethylene ether glycolterephthalate of 45:5:50.

Under a nitrogen atmosphere the temperature was raised to 215° C., andmethanol generated was removed by distillation as a liquid condensate.The temperature was held at 210° C. for about 1.5 hours until no moremethanol evolved, indicating the end of the transesterificationreaction.

The temperature was then raised to 250° C. and held at that temperatureat a pressure of 0.3 mm Hg for 3 hours. The polymer obtained could notsuccessfully be extruded into ribbons.

Example 1

This example illustrates the preparation of a polyether ester with thesame stoichiometry as that prepared in Comparative Example 1, but inthis case including trisodium phosphate nucleating agent.

A 25 gallon autoclave was charged with 33.2 lbs of dimethylterephthalate, 30 lbs of PO3G (Mn of 2440), 14 lbs of ethylene glycol, 2lbs of 1,4-butanediol, 80 g of ETHANOX® 330 antioxidant, 12 g of TYZOR®TPT as catalyst, and 136 g of trisodium phosphate as nucleating agent.The temperature was raised to 215° C., and methanol generated wasremoved with a nitrogen flush by distillation as a liquid condensate.The temperature was held at 210° C. for about 1.5 hours until no moremethanol evolved indicating the end of the trans-esterificationreaction.

The temperature was then raised to 250° C. and held at that temperatureat a pressure of 0.3 mm Hg for 2.5 hours. The polymer was extruded intoribbons and converted into flakes.

Comparative Example 2

This comparative example describes the synthesis of a polyether esterhaving 55 wt % polyethylene terephthalate hard segment and 45 wt %polytrimethylene ether terephthalate soft segment. No nucleating agentwas utilized.

A 250 ml three-necked flask was charged with 42.1 g of dimethylterephthalate, 29.3 g of PO3G (Mn of 1770), 20 g of ethylene glycol,0.15 g of IRGANOX® 1098 anti-oxidant (Ciba Specialty Chemicals Inc.),and 25 mg of TYZOR® TPT catalyst. The temperature was raised to 215° C.under nitrogen flush, and methanol generated was removed by distillationas a liquid condensate. The temperature was held at 210° C. for about1.5 hours until no more methanol evolved indicating the end oftransesterification reaction.

The temperature was then raised to 250° C. and held at that temperatureat a pressure of 0.2 mm Hg for 2 hours. The reaction was ended byremoving the heat and vacuum.

Example 2

This example illustrates the preparation of a polyether ester with thesame stoichiometry as that prepared in Comparative Example 2 butincluding trisodium phosphate nucleating agent.

A 250 ml three-necked flask was charged with 42.1 g of dimethylterephthalate, 29.3 g of PO3G (Mn of 1770), 20 g of ethylene glycol,0.15 g of IRGANOX® 1098 anti-oxidant, 25 mg of TYZOR® TPT catalyst, and0.36 g of trisodium phosphate (2100 ppm of sodium based on the finalpolymer) as nucleating agent. The temperature was raised to 215° C.under nitrogen, and the methanol generated was removed as a liquidcondensate by distillation. The temperature was held at 210° C. forabout 1.5 hours until no more methanol evolved, indicating the end oftransesterification reaction.

The temperature was raised to 250° C. and held at that temperature at apressure of 0.2 mm Hg for 2 hours. Then the reaction was stopped byremoval of the heat and vacuum, and the polymer was collected.

Example 3

A polyether ester was prepared as described in Example 2 except that theamount of trisodium phosphate used was 0.26 g (corresponding to 1700 ppmof sodium based on the final polymer).

Example 4

A polyether ester was prepared as described in Example 2 except thetrisodium phosphate of Example 2 was replaced with 0.41 g of sodiumacetate (corresponding to 1700 ppm of sodium based on the finalpolymer).

Example 5

This example describes synthesis of a polyether ester having 50 wt %polyethylene terephthalate hard segments and 50 wt % polytrimethyleneether terephthalate soft segments in the presence of trisodium phosphatenucleating agent

A 25 gallon autoclave was charged with 36.5 lbs of dimethylterephthalate, 30 lbs of PO3G (Mn of 1770), 16 lbs of ethylene glycol,87 g of ETHANOX® 330 antioxidant, 12 g of TYZOR® TPT catalyst, 22 gtrimethyl-trimellitate (1,2,4-benzene-tricarboxylic acid, methyl ester)and 150 g of sodium phosphate nucleating agent. The temperature wasraised to 215° C. under nitrogen, and the methanol generated was removedas a liquid condensate by distillation. The temperature was held at 210°C. for about 1.5 hours until no more methanol evolved, indicating theend of transesterification reaction.

The temperature was then raised to 250° C. and held at that temperatureat a pressure of 0.3 mmHg for 2.5 hours. The polymer was extruded intoribbons and converted into flakes.

The properties of the polymers prepared in the above examples are listedin Table 1.

TABLE 1 Effect of Nucleating Agents on Crystallization Temperature andHalf-Time T_(1/2) at Tm Trc ΔH 215° C. Ex. Composition Nucleating Agent(° C.) (° C.) (J/g) (min) C1 PET (45%) PBT (5%)/ None 227.5 142.4 9.96 —PO3G (50%) 1 PET (45%) PBT (5%)/ Na₃PO₄ (2100 ppm of Na) 230.0 183.919.4 6.40 PO3G (50%) C2 PET (55%)/PO3G None 244.6 174.1 24.4 8.18 (45%)2 PET (55%)/PO3G Na₃PO₄ (2100 ppm 241.9 214.3 24.8 0.23 (45%) of Na) 3PET (55%)/PO3G Na₃PO₄ (1700 ppm 235.9 214.1 29.5 0.30 (45%) of Na) 4 PET(55%)/PO3G NaAc (1700 ppm of 237.9 201.5 23.2 — (45%) Na) 5 PET(50%)/PO3G Na₃PO₄ (2100 ppm 233.0 187 16.5 3.20 (50%) of Na)

The increase in Trc and decrease in t_(1/2) suggest that the presence ofnucleating agent in the elastomer effectively increases thecrystallization rate.

The mechanical properties of the polymer prepared in Example 5 werecompared with those of HYTREL® 5556 polymer resin, a commercialthermoplastic elastomer available from E.I. duPont de Nemours andCompany. The data in Table 2 shows the excellent mechanical propertiesof the composition of the present invention.

TABLE 2 Property HYTREL ® 5556 Example 5 Soft segment Tg (° C.) −50 −63Hard segment Tm (° C.) 203 233 Hardness shore D 55 41 Tensile strength(psi) 3282 3156 % Elongation 448 616 Strength at 100% (psi) 2024 1340

From the data in Table 2, the polymer of Example 5 has uniquecombination of properties: a lower glass transition temperature, highermelt temperature, and excellent mechanical properties.

Example 6

This example demonstrates preparation of film from the nucleatedpolyether ester of Example 5.

The films were made using a 28 mm extruder (Werner & Pfleidener),equipped with Foremost #15 feeder, #3 casting drum, and #4 winder. Thehopper and throat of the extruder had a nitrogen blanket.

The polyether ester described in Example 5 was dried and fed through thehopper into the twin screw extruder. The sample was heated to melt andfed into a film die. The aperture of the die was set to roughly 5 milthickness (1 mil= 1/1000 inches=25.4 microns) and the film was extrudedcontinuously at the approximate rate of 3 feet per minute. The film wasthen cooled to 29° C. on a casting drum, which was equipped with acooling water jacket. The cooled film was then wound onto a roll with awinder.

The properties of the film are in Table 3.

TABLE 3 Properties of Polyether Ester Film Property Test Method Example6 Water Vapor Permeation Rate ASTM F1249 2733 (mil-gm/(m²-day)) OxygenPermeation Rate 8700 (mil-cc/(m²-day)) Stress at break (ksi) ASTMD882-02 2.767 Strain at break (%) 426

Example 7

This example describes synthesis of a polyether ester having 28 wt %polyethylene terephthalate hard segment and 72 wt % polytrimethyleneether terephthalate soft segment in the presence of trisodium phosphatenucleating agent.

A 25 gallon autoclave was charged with 19.8 lbs of dimethylterephthalate, 40 lbs of PO3G (Mn of 2270), 10.7 lbs of ethylene glycol,79.6 g of ETHANOX® 330 antioxidant, 24 g of TYZOR® TPT catalyst, and73.5 g of sodium phosphate nucleating agent. The temperature was raisedto 215° C. under nitrogen, and the methanol generated was removed as aliquid condensate by distillation. The temperature was held at 210° C.for about 1.5 hours until no more methanol evolved, indicating the endof transesterification reaction.

The temperature was then raised to 250° C. and held at that temperatureat a pressure of 0.3 mm Hg for 2.5 hours. The polymer was extruded intoribbons and converted into flakes. The polymer had a Tm of 216.5° C., aTrc of 184° C., and an IV of 1.105 dL/g.

Example 8 Fibers

Spinning Procedure—The polymer of Example 7 was extruded through a sandfilter spin pack and a three hole spinneret (0.3 mm diameter and 0.56 mmcapillary depth holes, maintained at 257-259° C. The filamentary streamsleaving the spinneret were quenched with air at 21° C., and converged toa bundle. The spinning conditions for the yarns are described in Table4.

The properties of the fibers obtained at two different winding speedsare reported in Table 4 (according to ASTM D2731 method).

TABLE 4 Spinning speed, mpm 1200 3000 Denier 80 54.5 Draw ratio 1.0 1.0% stretch for 5 cycle 200 200 Load at 100% (g/den) 0.247 0.238 Load at200% (g/den) 0.545 1.054 Load at 200% after 5 cycles 0.385 0.688 Unloadat 200% stretch (g/den) 0.311 0.553 Unload at 100% stretch (g/den) 0.0290.039 Tenacity (g/d) 0.829 1.262 Elongation (%) 282 235 Stress decay (%)19.3 19.9 Set (%) 22.5 16.1

1. A method for preparing a polyether ester elastomer, comprisingproviding and reacting: (a) a polymeric ether glycol componentcomprising at least about 50 wt % of a polytrimethylene ether glycol;(b) a diol component comprising at least about 50 mole % ethyleneglycol; and (c) a dicarboxylic acid equivalent, in the presence of thenucleating agent, wherein the nucleating agent comprises a metal cationselected from the group consisting of lithium, sodium, potassium andcalcium, and a anion selected from the group consisting of phosphate,sulfate and acetate; and wherein the thus-prepared polyether esterelastomer has a T_(rc) of at least 183.9° C. and a T_(1/2) of 6.4 min orless at 215° C.
 2. The method of claim 1 wherein the polyether esterelastomer comprises from about 10 to about 90 wt % polytrimethyleneether ester soft segment, and from about 10 to about 90 wt %polyethylene ester hard segment, based on the weight of the polyetherester elastomer.
 3. The method of claim 1 wherein the nucleating agentis present at a level of about 0.005 to about 2 wt %, based on theweight of the polyethylene ester hard segment.
 4. The method of claim 1wherein the diol component comprises at least about 95 to about 100 mole% ethylene glycol.
 5. The method of claim 1 wherein the polymeric etherglycol component comprises an oligomeric and/or polymeric ether glycolin which about 99 to 100% of the repeating units are trimethylene etherunits.
 6. The method of claim 1 wherein the polytrimethylene etherglycol is prepared by the acid catalyzed polycondensation of monomerscomprising at least 50 mole % 1,3-propane diol.
 7. The method of claim 6wherein the 1,3-propane diol is derived from a fermentation processusing a renewable biological source.
 8. The method of claim 1 whereinthe polytrimethylene ether glycol has number average molecular weight offrom about 250 to about
 5000. 9. The method of claim 1 wherein thedicarboxylic acid equivalent is selected from the group consisting ofterephthalic acid, dimethyl terephthalate and mixtures thereof.
 10. Themethod of claim 1 comprising the steps of (a) heating (i) a polymericether glycol component comprising at least about 50 wt % of apolytrimethylene ether glycol, (ii) terephthalic acid and/or dimethylterephthalate, (iii) a molar excess of a diol component comprising atleast about 75 mole % ethylene glycol, and (iv) the nucleating agent, inthe presence of a catalyst at a temperature in the range of from about150° C. to about 250° C. while removing water or methanol by-product toform a precondensation product; and (b) polymerizing the precondensationproduct under vacuum at temperature in the range of from about 220° C.to about 290° C. while removing excess diol component to form apolyether ester having polytrimethylene ether terephthalate soft segmentand polyethylene terephthalate hard segment.
 11. The method of claim 1comprising the steps of (a) heating (i) a polymeric ether glycolcomponent comprising at least about 50 wt % of a polytrimethylene etherglycol, (ii) terephthalic acid and/or dimethyl terephthalate, and (iii)a molar excess of a diol component comprising at least about 75 mole %ethylene glycol, in the presence of a catalyst at temperature in therange of from about 150° C. to about 250° C. while removing water and/ormethanol by-product to form a precondensation product; (b) adding thenucleating agent to the precondensation product, and (c) polymerizingthe precondensation product under vacuum at a temperature in the rangeof from about 220° C. to about 290° C. while removing excess diol toform a polyether ester having polytrimethylene ether terephthalate softsegment and polyethylene terephthalate hard segment.
 12. The method ofclaim 1 additionally comprising the step of forming the polyether esterelastomer into a shaped article.
 13. The method of claim 12 wherein theshaped article is a fiber.
 14. The method of claim 12 wherein the shapedarticle is a flexible film.